1. Field of the Invention
This invention relates to a video data processing apparatus such as a two-dimensional (2D) or three-dimensional (3D or stereoscopic) video data processing apparatus. This invention also relates to a picture reproducing apparatus such as a 2D, 3D, or stereoscopic picture reproducing apparatus. In addition, this invention relates to a computer program for processing video data such as 2D, 3D, or stereoscopic video data. This invention also relates to a computer program for reproducing 2D, 3D, or stereoscopic pictures. In addition, this invention relates to a method of processing video data such as 2D, 3D, or stereoscopic video data. Furthermore, this invention relates to a method of reproducing 2D, 3D, or stereoscopic pictures. This invention also relates to a recording medium storing video data such as 2D, 3D, or stereoscopic video data.
2. Description of the Related Art
Digital technologies and computer graphics provide various methods of virtually indicating three-dimensional (3D) pictures on the basis of two-dimensional (2D) pictures. Indicated virtual 3D pictures basically different from actual 3D images perceived by human beings. Studies have been made as to the influence of the viewing of virtual 3D pictures on human beings, and whether or not the viewing of virtual 3D pictures is safe for human beings. The results of the studies reveal that the viewing of virtual 3D pictures tend to affect the viewer's visual sensation, for example, the sensation of the depth of an actual 3D object. In addition, it has been found that the unnatural visual sensation of the depth of an actual 3D object adversely affects a human body.
Japanese proposed guidelines on 3D pictures, “Feasibility Study on Development of System for Generally Assessing Influence of 3D pictures on Human Body”, published by the Machine System Promotion Society in July 2002, report that the exposure of human eyes to virtual 3D pictures using the binocular parallax and the motion parallax inevitably affects human bodies.
Examples of viewer-related items concerning the influence of the display of pictures on human bodies are the age, the degree of immersion in the pictures, the visual sensation, the autonomic nervous system, the viewing environments, and the viewing time. Examples of contents-related items are the spatial frequency, the temporal frequency, the resolution, the contrast, the flicker, and the distortion. These viewer-related and contents-related items are applicable to not only 2D pictures but also virtual 3D pictures. Other examples of viewer-related items applicable only to virtual 3D pictures are the binocular parallax and the convergence.
The above-indicated Japanese proposed guidelines point out that the viewing of virtual 3D pictures using the binocular parallax and the motion parallax in childhood may adversely affect the growth of the visual sensation. The Japanese proposed guidelines disclose the conditions of the typical growth of the cornea, the retina, the stereopsis, the fringe acuity, the blink reflex to an electric impulse, the optic nerve, the blink reflex to a light impulse, and the focus adjustment in children 0 to 10 years old. The disclosure shows that there are stages during which some of these functions actively grow and stages during which they grow not so actively.
Japanese report “Meeting for Investigation on Broadcasting and Visual and Hearing Sensations”, published on Jun. 28, 1998, put on the Internet web site <URL: http://www.johotsusintokei.soumu.go.jp/whitepaper/ja/h11/press/japanese/housou/0626j12.htm>, indicates that a popular animation television program caused hundreds of child viewers to have a fit of photosensitive epilepsy on Dec. 16, 1997 in Japan. The Japanese report further indicates that stimulative 12-Hz flashing images in the program caused a fit of photosensitive epilepsy, and those images had a red-blue mixed color. The Japanese report discloses light-related factors having the effect of creating reaction in viewer's brain which may cause a fit of photosensitive epilepsy in a viewer. The light-related factors are flashing light having a frequency of 10 to 30 Hz, and dense patterns of the recurrence of simple figures. According to the Japanese report, red flashing light is greater than white flashing light in the effect of creating reaction in viewer's brain. A stripe pattern, a polka-dot pattern, a checker pattern, and a scroll pattern are relatively great in the effect of creating reaction in viewer's brain. As the contrast of these patterns increases, the effect of creating reaction in viewer's brain strengthens. The spatial frequency of a simple-figure-recurrence pattern affects the strength of the effect of creating reaction in viewer's brain. Especially, a stripe pattern or a checker pattern having a spatial frequency of 2 to 4 Hz with respect to a visual angle of 1° is considerably great in the effect of creating reaction in viewer's brain.
In the United Kingdom, there are guidance notes to program and sponsor ship codes, “ITC Guidance Note for Licensees on Flashing Images and Regular Patterns in Television”. First introduced by the ITC in 1994, the Guidance Note provides licensees with information to help them reduce the risk of television material causing seizures in viewers with photosensitive epilepsy, a condition affecting young people in particular. The ITC held a detailed review of the Guidance Note during 2000, working closely with medical experts and representatives from licensees. The resulting revised Guidance Note was published in July 2001 after having been put out for consultation.
Accordingly, television program producers have recently been required to express pictures in such a way as to be capable of reducing the adverse influence of the expressed pictures on viewer's bodies.
Japanese patent application publication number 2003-157136 discloses a high-presence video display system capable of recording biological reaction of a user. The system in Japanese application 2003-157136 includes a measuring section, a recording section, a judging section, a controlling section, and a display section. The measuring section has a pair of probe electrodes to be attached to the skin of a user. First, the system operates in a registration mode during which the measuring section detects the voltage between the probe electrodes attached to the skin of the user. The detected voltage represents the biological reaction of the user which contains brain waves or electrocardiographic waves. During the registration mode of operation, the user may make prescribed motion or action of user's eyes or muscles. In this case, the detected voltage represents the biological reaction of the user to that motion or action. The recording section stores the detected voltage as an indication of the biological reaction of the user. This operation step corresponds to the registration of the user (the registration of the biological reaction of the user). After the registration mode of operation, a normal mode of operation is implemented. During an initial stage of the normal mode of operation, an identifying procedure is performed. Specifically, the measuring section is activated, and the biological reaction judging section compares the biological reaction represented by the detected voltage currently outputted from the measuring section with the registered biological reaction in the recording section to decide whether or not the present user is the same as the registered user. The controlling section controls the display section in response to the result of this identifying decision.
U.S. Pat. No. 6,212,329 corresponding to Japanese patent application publication number 07-235131/1995 (Japanese patent number 2853727) discloses an apparatus for reproducing an original signal conveyed as main data by a data medium such as a recording disk or a broadcasting system. Medium protection data which are specific to the data medium are conveyed together with the main data. The reproducing apparatus in U.S. Pat. No. 6,212,329 includes a section for generating apparatus protection data specific to the apparatus, a section for combining the apparatus protection data with the medium protection data to define a protection level, and a section for applying the protection level to restrict the reproduction of the original signal. The degree of the restriction is varied in stepwise depending on the protection level. The medium protection data may include information for implementing restricted reproduction of portions of the original signal by providing given regions in specified frames of the original signal with a degraded resolution.
U.S. Pat. No. 6,515,709 discloses an image display apparatus including an extracting unit, a setting unit, a converting unit, and a display unit. The extracting unit extracts, from image information, risk factors harmful to a biological body, that is, the body of a user. The risk factors may be those harmful to persons having photosensitive epilepsy. The risk factors are, for example, a repetitive stimulative image having a frequency higher than 3 Hz, a blurred image, and an oblique-swung image. The setting unit is operated by a user, and sets safety levels for harmful factors in accordance with user's request. The harmful factors correspond to ones selected from the risk factors extracted by the extracting unit. The converting unit changes the harmful factors in the image information to the safety levels to generate conversion-result image information. The change of the harmful factors to the safety levels involves, for example, cutting off a repetitive image having a frequency higher than 3 Hz, reducing the spectrum intensity of a repetitive image having a frequency higher than 3 Hz, reducing the frequency of a 10-Hz or higher repetitive image, and changing the color of a red-based repetitive image having a frequency higher than 3 Hz. The display unit visualizes the conversion-result image information.
Japanese patent application publication number 2004-246725 discloses a display system for indicating 3D contents to a user in an optimal manner. The display system in Japanese application 2004-246725 controls the display conditions of 3D contents in response to prescribed factors. The controlled display conditions include the brightness, the contrast, the display rate, and the depth-related condition. The prescribed factors include the degree of the biological influence of indicated 3D contents on a viewer, the degree of viewer's feeling of physical disorder caused by indicated 3D contents, and the viewer's resistivity to indicated 3D contents. In Japanese application 2004-246725, a combination of 3D contents and accessory information related to the 3D contents is transmitted from a server of a contents producer side to the display system. The accessory information represents the attributes of the 3D contents, for example, the frame size, the luminance, the contrast, and the depth-related condition of the 3D contents. The accessory information also represents standard attribute values (average attribute values) corresponding to the respective contents attributes. The display system calculates the degree of the biological influence of indicated 3D contents on a viewer from the differences between the standard attribute values and the contents attributes which are represented by the transmitted accessory information. The display system controls the display conditions of the 3D contents in response to the calculated influence degree.